At this point, Sanders would have to achieve upset wins in several remaining states – like New York, Pennsylvania and California -- in order to catch up in pledged delegates.

California would be a major win if Sanders could pull it off, though the state tends to lean more towards Clinton.

The self-described Democratic socialist has also failed to win the African American vote, which has clung onto Clinton. Despite his use of racial justice and equality as a major campaign focus, Sanders has had a tough time extending his reach past white, liberal voters.

As long as Clinton holds on to that demographic, nearly half of the expected vote, it hinders Sanders’ chances of winning.

It’s worth noting, however, that the South -- undeniably pro-Clinton -- has seen the majority of elections thus far.

A reminder: The math isn’t taking into account superdelegates, who are free to support any candidate at the party’s national convention in July. Though superdelegates tend to stick to the popular vote, Sanders has a chance to win them over if he starts catching up.

With plenty of money in his campaign, Sanders will have no problem holding out for the possibility of a turn of tides.

After all, Clinton could still be indicted for the email scandal working its way through a federal probe, which could drastically change the race.